/*
 *
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 *  * or more contributor license agreements.  See the NOTICE file
 *  * distributed with this work for additional information
 *  * regarding copyright ownership.  The ASF licenses this file
 *  * to you under the Apache License, Version 2.0 (the
 *  * "License"); you may not use this file except in compliance
 *  * with the License.  You may obtain a copy of the License at
 *  *
 *  *    http://www.apache.org/licenses/LICENSE-2.0
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 *  * Unless required by applicable law or agreed to in writing,
 *  * software distributed under the License is distributed on an
 *  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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package org.apache.usergrid.persistence.core.migration.data;


/**
 * Data migration.  The internal version to migrate
 *
 * @param
 */
public interface DataMigration {

    /**
     * Perform the migration, returning an observable with a single emitted value
     * @param currentVersion the current version of the system
     * @param observer The observer to receive updates of the progress
     *
     * @return The version that the system is now running
     */
    int migrate( final int currentVersion, ProgressObserver observer );

    /**
     * Check if this version supports migration from the current system version.  If this returns false,
     * migrate will not be invoked
     * @return
     */
    boolean supports( final int currentVersion );

    /**
     * Get the max version this migration can migrate to
     * @return
     */
    int getMaxVersion();


}
